There's one go-to recipe I believe all bakers need: a single-layer cake. There's a time and place for multi-layered cake (usually birthdays and other celebrations). But a single-layer cake isn't about celebration, it's about simplicity.
My love for single layer cakes comes from my mom. Occasionally, I'd come home from school and find one sitting on the counter. It was always a yellow cake, iced with chocolate buttercream, and, if she felt like dressing it up, a single maraschino cherry in the center. Before baking, she'd throw a couple of chocolate chips into the batter. She said whoever got the slice with the chips was guaranteed a "good luck day." Who am I to argue with that mom-logic?
The yellow single-layer cake I bake tastes very similar to the ones I ate growing up. It's just butter, sugar, eggs, and gluten-free flour. The funny thing is the method. It doesn't require you to cream the butter and sugar together. You simply dump all the ingredients into a bowl and mix. That's it. The only thing to watch out for is the butter. You want it soft. Not melty. Not microwaved where the ends are hard and it's melted in the center. You want the butter soft.
If you don't have room-temperature butter ready when you want to bake this cake, try this trick: set up a double boiler. (Nest a small bowl on top of a small pot of very hot but not boiling water. You don't want the water to touch the bottom of the bowl.) Place the butter, still wrapped, into the bowl. Turn the stick every few minutes until it's soft. If you're microwave is gentle enough, go ahead and soften the butter in the microwave. Use a very low setting and heat the butter in 15 second bursts, then turn the stick. If you are very careful, this works. I've noticed that if I stand my butter up while nuking the center doesn't melt but that could just be my microwave.
As for finishing the cake, ice it with a simple buttercream. Or not. This cake works well without any type of icing. If you don't want buttercream but want to finish the cake with something, I'd strongly recommend a citrus glaze. I prefer lemon but any citrus works. Stir together some powdered sugar and a little milk (or water) until you have a thick glaze. Then add the zest of your favorite citrus and pour the glaze over the top of the cake.
From start to cooling, this cake takes less than an hour to make. Of that time, only about fifteen minutes requires any activity. So remember this recipe on a busy days when you want a little something sweet but don't have the time—or the energy—to do much in the kitchen.